Monday, August 30, 2010
Sunday, August 29, 2010
The fungus feeds during the winter when the tree is at its weakest. With the onset of Spring, the tree's vigor improves as leaves emerge and photosynthesis begins. When sugars reach the injured site new callus tissue forms and stops the spread of the fungus. This callus tissue is invaded and killed as soon as the fungus regains control of the tree. This cycle happens again and again until the tree no longer has the tissue necessary to keep the tree together. At some point this tree will break at the canker.
The fungus that causes this problem, known as Black, Target and Ceratocystis canker, is Ceratocystis fimbriata.
Applying nitrogen around the tree after the leaves emerge in the spring will increase tree health. Two pounds of nitrogen per 1000 square foot area surrounding the tree is the recommended amount to use. Unless you have had a soil test conducted that shows phosphorus and/or potassium levels are deficient, these nutrients should NOT be applied. Ammonium sulfate is a good synthetic nitrogen source to use. Blood meal, cotton seed meal, corn gluten and other organic products are also good nitrogen fertilizers.
Note: The cat scratches on the trunks are cause for concern. There is a good chance this fungus will be spread to the other trees by the claws of the cat. Removing the infected trunk will help prevent the spread of the fungus.
Wednesday, August 25, 2010
|Dead Shoot as a reult of this insect|
If these galls are in the main stem of the tree, can the area damged by this insect break off?
An application of imidiclopyrid once a year will take care of this problem.
|Note Exit Holes|
Tuesday, August 24, 2010
|Charleston Gray and other melons can suffer from sunburn|
While the black spots and smugs caused by fungus are often thought to be the cause of the problem, the intense rays of the sun not providing shade is the problem.
|Cucumber with sunburn and a fungus infection.|
Covering the fruit with the vines, straw or hay can help prevent this problem.
Monday, August 23, 2010
This year's spring was ideal for these diseases. Control is an option that requires frequent sprays from bud break until the weather conditions change. As soon as warm weather arrives the infection cycle of the disease organism is shut down.
At this time of year there is no reason to spray. Cleaning up the leaves in the fall may reduce a source of this disease for next year's infection cycle.
The sprays and spray schedule recommended for Sycamore anthracnose should be followed if you want to prevent anthracnose. If next spring is warm and dry, there is no reason to spray.
Friday, August 20, 2010
You can tell by the one Susan Swift is holding they can become quite long and certainly do resemble a serpent.
If you aren't familiar with this cucumber, they stay tender no matter how long they grow.
The only problem I've had with this cultivar is they split along the stem end. The damage shows up as open sores which enlarge into large splits as seen below.
This problem may be due to too much soil moisture. Slicing cucumbers tend to become bitter when they lack adequate soil moisture. Which is worse, a cucumber that is bitter or one that splits open?
Thursday, August 19, 2010
This photo of an ash tree shows symptoms of glyphosate uptake. Glyphosate, initially sold as Roundup by Monsanto, is now available in generic form at many farm cooperatives, and retail businesses. When this product is misapplied it can cause damage. In this case the owner sprayed glyphosate to control weeds at the base of the tree last year. These symptoms appeared this year.
Glyphosate may drift onto the buds or be taken in through green tissue at the base of tree .
Symptoms of glyphosate toxicity the year after glyphosate uptake results in clusters of leaves where shoots should develop. I've seen these same symptoms on trees in local retail nurseries where the wholesale nursery applied glyphosate to control weeds around the trees the previous year. These symptoms are also occasionally seen on grape vines when glyphosate is used to control weeds at the base of the vines.
Herbicides should be used with care. Don't assume they are safe.
Monday, August 16, 2010
The first syptoms you will see are white spots on the leaves. These spots increase and eventually cover the leaf. This disease reduces the sugars and starches necessary for the development and sizing of the fruit.
Controlling this disease is quite easy if you use the correct product or combination of materials. Some people use SunLite oil in combination with baking soda as a spray. A better product to use is potassium bicarbonate. Baking soda can damage plant cells; potassium bicarbonate is much softer in its activity. Neem oil is also reported to be an effective control of powdery mildew. Your local nursery or garden center should have one of these products on their shelves.
These products are best applied in the evening as they remain in the liquid state for a longer period of time. If a rain occurs shortly after you make the application you will most likely need to reapply the product. You will still see spots on the leaves even after you treat for this disease, but as long as the spots don't enlarge or more spots don't develop, the infection has been stopped. Follow the label to ensure you apply these at the proper dilution and frequency.
Sunday, August 15, 2010
If you leave pumpkins and winter squash on the vine even though they are ready to harvest, you run the risk of them being damaged by insects or vandals.
Harvest your pumpkins and winter squash as soon as they are ready. If you can cut their rind with a finger nail they are not ready to harvest; when the rind can no longer be cut with a finger nail they need to be harvested.
Always leave a portion of the stem attached to the fruit. Otherwise you run the risk of a disease organism invading the fruit causing rot.
Friday, August 13, 2010
Unless you look closely, it looks like maggots are growing under the skin of this tomato. In this photo I removed the skin of the tomato to give you a closer look. Who would want to eat a tomato riddled with maggots?
Some of these ‘maggots’ have even pushed through the skin and are invading the air space surrounding this tomato. In the photo immediately below you can see other 'maggots' that have escaped through the skin and others that are about to escape.
These ‘maggots'’ turn out to be tiny tomato plants. The seeds germinated inside the fruit and the baby seedlings pushed their way to and even through the skin of the tomato. This is called vivipary.
Why did the seeds germinate and begin to grow? Seed dormancy is usually terminated by low temperatures or by the application of a plant growth substance such as ethephon.
Ethephon is often applied to tomatoes to enhance ripening or to ensure all the tomatoes in an order are the same shade of red when they arrive at the grocer. Was this tomato treated with ethephon or was another substance applied? Or did something else trigger the germination of the seeds?
Wednesday, August 11, 2010
Four to five hundred tons of this fungus are sold in Mexico City every year. In the United States, increased interest in this fungus is due to an increase in the Mexican-American community and the rising interest in new foods. Chefs in high-end restaurants are reported to pay $30 to $40 for 2 pounds of this mushroom.
Caused by the fungus Ustilago maydis, corn smut, is called huitlacoche by those in the know. Like puffballs, the gleba, the inner spore bearing mass, is initaily nice and white, turning into black spores as seen with the smut ball on the left side of this photo. That smut ball has broken open releasing black spores.
Even small backyard producers may find the production of huitlacoche profitable. If you are interested, check out Purdue University's article on how to produce this unusual agricultural product.
Hackberry (Celtis spp.) leaves often have spots on the upper surface that looks somewhat like measles or blisters but are light green or yellow in color.
These spots are caused by the Hackberry Blistergall maker (Pachypsylla celtidisvesicula). The blisters are 3 to 4 mm in diameter and only slightly raised from the leaf surface.
There are 25 millimeters (mm) in an inch so these spots are quite small.
Tuesday, August 10, 2010
Sunday, August 8, 2010
The tomatillo or husk-tomato produces a great fruit wrapped in a husk. In the case of the larger-fruited types, when the husk is still green and the fruit has not filled the husk, the fruit is not yet ready to harvest.
If you grow the large-fruited type of tomatillo, they are best harvested when the husk has changed color, and the fruit has broken through and turned yellow-green. I have been told tomatillo are best used before the seeds are well developed.
If you have better suggestions on how to determine when to harvest this fruit leave a comment.
We all know tomato fruit splits due to uneven soil moisture (i.e. wet and dry period) and/or the inability of the plant to take up enough moisture during fruit development.
When moisture uptake is limited, tomato fruit stops enlarging and the skin of the fruit goes from the consistency of flexible rubber to the consistency of a brittle plastic. When the plant again moves water to the fruit, the fruit begins to enlarge and the skin cracks.
The cracks on some varieties of tomatoes will form concentric circles around the stem while other varieties will crack from the stem end toward the blossom end. To prevent this from happening we need to keep the soil uniformly moist and improve conditions that will allow the roots to move water to the leaves and fruit.
When some tomatoes crack and again start to grow, they grow out of the crack producng strange looking fruit. Split fruit are also highly susceptible to various rots.
Tuesday, August 3, 2010
Monday, August 2, 2010
“Codling moth (CM): We are still catching substantial numbers of second generation moth in our traps. It suggests us that we need protection against this pest beyond August 1. You also may need an additional spray beyond August 1 depending upon the activity of moths, the protection window of your insecticide used and harvesting date.
Peach Twig Borer (PTB): We are catching higher numbers (more than previous weeks) of second generation PTB month in our traps. This suggests a need to protect crop against this generation. Control of this generation is important as this generation can feed on fruits.
Crown Borer: The Crown borers are active in our orchard. Please, remember to have two sprays (a cover and a follow-up spray) to protect your crop from this pest. If this borer is active even after second spray, we might need a third spray during fall (trunk spray). Keep eye on this pest.”
To ensure good quality fruit and the survival of your fruit trees, treatments for these pests need to be applied and/or continued. Information on these pests and their control is available at http://www.ext.colostate.edu/pubs/garden/02800.html and http://www.ext.colostate.edu/pubs/garden/02804.html .
If you have specific questions call my office at 970 244-1836.